salak

A layered configuration loader with zero-boilerplate configuration management.

About

salak try to provide an out-of-box configuration loader for creating new apps, such as cli, web, servers.

Multi-Layered source environment.

salak defines following default PropertySources: 1. Command line arguments using clap to parsing -P, --propery KEY=VALUE. 2. System Environment. 3. app.toml(*) in current dir and $HOME dir. Or if you specify APP_CONF_DIR dir, then only load toml in this dir.

* APP_CONF_NAME can be specified to replace app.

Placeholder format

1. ${key:default} means get value of key, if not exists then return default.
2. ${key} means get value of key, if not exists then return PropertyError::NotFound(_).

Key format

1. a.b.c is a normal key separated by dot(.).
2. a.b[0], a.b[1], a.b[2]... is a group of keys with arrays.
3. System environment key will be changed from HELLO_WORLD <=> hello.world, HELLO__WORLD_HOW <=> hello_world.how, hello[1].world => HELLO_1_WORLD <=> hello.1.world.

Auto derived parameters.

attribute default to set default value.

1. #[salak(default="string")]
2. #[salak(default=1)]

attribute disable_placeholder to disable placeholder parsing.

1. #[salak(disable_placeholder)]
2. #[salak(disable_placeholder = true)]

Features

Default features

1. enable_log, enable log record if enabled.
2. enable_toml, enable toml support.
3. enable_derive, enable auto derive [FromEnvironment] for struts.

Optional features

1. enable_clap, enable default command line arguments parsing by clap.

Quick Code

```rust use salak::*;

[derive(FromEnvironment, Debug)]

pub struct DatabaseConfig { url: String, #[salak(default = "salak")] name: String, #[salak(default = "${database.name}")] username: String, password: Option, #[salak(default = "${Hello}", disable_placeholder)] description: String, }

fn main() { std::env::setvar("database.url", "localhost:5432"); let env = SalakBuilder::new() .withdefaultargs(autoreadsysargs_param!()) // This line need enable feature enable_clap. .build();

match env.require::("database") { Ok(val) => println!("{:?}", val), Err(e) => println!("{}", e), } } // Output: DatabaseConfig { url: "localhost:5432", name: "salak", username: "salak", password: None, description: "${Hello}" } ```

Quick Run

```bash git clone https://github.com/leptonyu/salak.rs.git cd salak.rs cargo run --example salak --features="default enable_clap" -- -h

salak 0.4.0

Daniel Yu leptonyu@gmail.com

A rust configuration loader

USAGE:

salak [OPTIONS]

FLAGS:

-h, --help Prints help information

-V, --version Prints version information

OPTIONS:

-P, --property ... Set properties

```

TODO

1. Support hashmap.
2. Reload configurations.